Color conversion element and display device including the same

ABSTRACT

Provided are a wavelength conversion layer and a display device. A color conversion element comprises: a wavelength conversion layer; one or more low refractive layers which are disposed on and/or under the wavelength conversion layer and have a lower refractive index than the wavelength conversion layer; and one or more capping layers which are disposed between the wavelength conversion layer and the low refractive layers and/or on a surface opposite to a surface of each of the low refractive layers which faces the wavelength conversion layer.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and the benefit of Korean PatentApplication No. 10-2017-0139105, filed on Oct. 25, 2017, and KoreanPatent Application No. 10-2018-0105588, filed on Sep. 4, 2018, in theKorean Intellectual Property Office, the entire content of each of whichis incorporated herein by reference.

BACKGROUND 1. Field

The present disclosure relates to a color conversion element and adisplay device including the same.

2. Description of the Related Art

A display device may include a color conversion element that receiveslight from a light source, such as an organic light emitting diode, andrealizes a color. The color conversion element may be provided in thedisplay device in the form of a substrate or may be integrated directlywith elements within the display device. In an example, the colorconversion element may receive blue light from the light source and emitblue, green and red light, so that an image having various suitablecolors can be displayed. In this case, the green light and the red lightmay be realized by converting the received blue light, and the bluelight may be realized by emitting the received blue light as it is or byscattering the received blue light to improve the viewing angle.

However, when light provided from the light source transmits through alayer containing wavelength conversion particles or a scatterer, it canbe absorbed or scattered back to the light source by a filter layerwithout being converted into green and red light. Such light loss canreduce light efficiency, luminance, etc.

SUMMARY

Aspects of embodiments of the present disclosure provide a colorconversion element capable of improving light efficiency, luminance,etc. by recycling light that is lost in the process of transmittingthrough a layer containing wavelength conversion particles or ascatterer, and a display device including the color conversion element.

However, aspects of embodiments of the present disclosure are notrestricted to the ones set forth herein. The above and other aspects ofembodiments of the present disclosure will become more apparent to oneof ordinary skill in the art to which the present disclosure pertains byreferencing the detailed description of provided below.

According to an aspect of an embodiment of the present disclosure, thereis provided a color conversion element comprising: a wavelengthconversion layer; one or more low refractive layers which are disposedon and/or under the wavelength conversion layer and have a lowerrefractive index than the wavelength conversion layer; and one or morecapping layers which are disposed between the wavelength conversionlayer and the low refractive layers and/or on a surface opposite to asurface of each of the low refractive layers which faces the wavelengthconversion layer.

According to another aspect of an embodiment of the present disclosure,there is provided a display device comprising: a display element; and acolor conversion element which is disposed on the display element,wherein the color conversion element comprises: a base substrate; awavelength conversion pattern layer which is disposed on the basesubstrate; a first low refractive layer which is disposed between thebase substrate and the wavelength conversion pattern layer and/or asecond low refractive layer which is disposed on the wavelengthconversion pattern layer; and one or more capping layers which aredisposed on and/or under the first low refractive layer and/or thesecond low refractive layer, wherein each of the first low refractivelayer and the second low refractive layer has a lower refractive indexthan the wavelength conversion pattern layer.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects will become apparent and more readilyappreciated from the following description of the embodiments, taken inconjunction with the accompanying drawings in which:

FIG. 1 is a cross-sectional view of a color conversion element accordingto an embodiment;

FIG. 2 is an enlarged view of a portion A of FIG. 1;

FIG. 3 is an enlarged view of a portion B of FIG. 2;

FIG. 4 is a cross-sectional view of a display device according to anembodiment;

FIG. 5 is a cross-sectional view of a color conversion element accordingto an embodiment;

FIG. 6 is an enlarged view of a portion C of FIG. 5;

FIG. 7 is a cross-sectional view of a color conversion element accordingto an embodiment;

FIG. 8 is an enlarged view of a portion D of FIG. 7;

FIGS. 9-12 are cross-sectional views of color conversion elementsaccording to embodiments; and

FIG. 13 is a cross-sectional view of a display device according to anembodiment.

FIG. 14 is a cross-sectional view of a display device according to anembodiment.

FIG. 15 is a cross-sectional view of a display device according to anembodiment.

DETAILED DESCRIPTION

Features of embodiments of the present disclosure and methods ofaccomplishing the same may be understood more readily by reference tothe following detailed description of embodiments and the accompanyingdrawings. The subject matter of the present disclosure may, however, beembodied in many different forms and should not be construed as beinglimited to the embodiments set forth herein. Rather, these embodimentsare provided so that this disclosure will be thorough and complete andwill fully convey the concepts and features of the subject matter of thepresent disclosure to those skilled in the art, and the invention willonly be defined by the appended claims, and equivalents thereof.

It will be understood that when an element or layer is referred to asbeing “on,” “connected to” or “coupled to” another element or layer, theelement or layer can be directly on, connected or coupled to anotherelement or layer or intervening elements or layers. In contrast, when anelement is referred to as being “directly on,” “directly connected to”or “directly coupled to” another element or layer, there are nointervening elements or layers present. As used herein, connected mayrefer to elements being physically, electrically and/or fluidlyconnected to each other.

It will be understood that, although the terms first, second, third,etc., may be used herein to describe various elements, components,regions, layers and/or sections, these elements, components, regions,layers and/or sections should not be limited by these terms. These termsare only used to distinguish one element, component, region, layer orsection from another element, component, region, layer or section. Thus,a first element, component, region, layer or section discussed belowcould be termed a second element, component, region, layer or sectionwithout departing from the spirit and scope of the present disclosure.

The terminology used herein is for the purpose of describing thedisclosed embodiments only and is not intended to be limiting. As usedherein, the singular forms “a,” “an” and “the” are intended to includethe plural forms as well, including “at least one,” unless the contextclearly indicates otherwise. It will be further understood that theterms “comprises,” “comprising,” “includes” and/or “including,” whenused in the present disclosure, specify the presence of stated features,integers, operations, elements, and/or components, but do not precludethe presence or addition of one or more other features, integers, steps,operations, elements, components, and/or groups thereof. “At least one”is not to be construed as limiting “a” or “an.” “Or” means “and/or.” Asused herein, the term “and/or” includes any and all combinations of oneor more of the associated listed items.

Spatially relative terms, such as “beneath,” “below,” “lower,” “above,”“upper” and the like, may be used herein for ease of description todescribe one element or feature's relationship to another element(s) orfeature(s) as illustrated in the figures. It will be understood that thespatially relative terms are intended to encompass differentorientations of the device in use or operation in addition to theorientation depicted in the figures. For example, if the device in thefigures is turned over, elements described as “below” or “beneath” otherelements or features would then be oriented “above” the other elementsor features. Thus, the exemplary term “below” can encompass both anorientation of above and below.

Hereinafter, embodiments will be described with reference to theaccompanying drawings.

FIG. 1 is a cross-sectional view of a color conversion element 1according to an embodiment, and FIG. 2 is an enlarged view of a portionA of FIG. 1.

Referring to FIGS. 1-2, the color conversion element 1 includes a basesubstrate 100, a light shielding member BM, wavelength conversionpattern layers 320, a light-transmitting pattern layer 310, and aplurality of low refractive layers 400 a and 400 b. In addition, thecolor conversion element 1 may further include a first wavelength bandfilter layer 210, a second wavelength band filter layer 220, and anovercoat layer 500.

The base substrate 100 may support components of the color conversionelement 1 by providing a space for accommodating the wavelengthconversion pattern layers 320, the low refractive layers 400 a and 400b, etc. located on the base substrate 100. The base substrate 100 may bea light transmitting substrate. In an embodiment, when the colorconversion element 1 is coupled to a display element 10, an upper partof the color conversion element 1 based on FIG. 1 may be placed to facethe display element 10 and then bonded to the display element 10 (seeFIG. 4). In this case, light provided from the display element 10 may betransmitted through the base substrate 100 from an upper surface of thebase substrate 100 toward a lower surface of the base substrate 100based on FIG. 1.

The light shielding member BM is disposed on the base substrate 100. Anarea where the light shielding member BM is disposed in a plan view maybe an area where the transmission of visible light is substantiallyblocked, and an area where the light shielding member BM is not disposedmay be a light transmitting area. In an embodiment, the light shieldingmember BM may include an organic material including a blue colorant, andthe organic material may include a photosensitive organic material.

The light shielding member BM may be disposed in a predetermined (orset) pattern. For example, the light shielding member BM may be disposedbetween adjacent ones of the wavelength conversion pattern layers 320and the light-transmitting pattern layer 310 located on the lightshielding member BM.

The light shielding member BM may include a material having a highabsorption rate for visible light. In an embodiment, the light shieldingmember BM may include a metal such as chrome, a metal nitride, a metaloxide, or a resin material colored in black.

The light shielding member BM can improve color reproducibility bypreventing color mixing between adjacent ones of the wavelengthconversion pattern layers 320 and the light-transmitting pattern layer310 (or by reducing a likelihood or amount of such color mixing).

The wavelength conversion pattern layers 320 and the light-transmittingpattern layer 310 may be disposed on the base substrate 100 in the areawhere the light shielding member BM is not disposed. However,embodiments are not limited to this case, and a portion of thewavelength conversion pattern layers 320 and/or the light-transmittingpattern layer 310 can also be disposed on the light shielding member BMto overlap at least a portion of the light shielding member BM. Inaddition, the wavelength conversion pattern layers 320 and thelight-transmitting pattern layer 310 may be, but not necessarily, spacedapart from each other by a predetermined (or set) distance.

The wavelength conversion pattern layers 320 may include a firstwavelength conversion pattern layer 320 a and a second wavelengthconversion pattern layer 320 b. The first wavelength conversion patternlayer 320 a, the second wavelength conversion pattern layer 320 b, andthe light-transmitting pattern layer 310 may be arranged on the basesubstrate 100 in a predetermined (or set) order or rule. For example,the first wavelength conversion pattern layer 320 a, the secondwavelength conversion pattern layer 320 b, and the light-transmittingpattern layer 310 may be arranged in a specific (or set) pattern in aplan view. In the drawings, the light-transmitting pattern layer 310,the first wavelength conversion pattern layer 320 a and the secondwavelength conversion pattern layer 320 b are arranged sequentially inthis order. However, the arrangement order or rule of thelight-transmitting pattern layer 310, the first wavelength conversionpattern layer 320 a and the second wavelength conversion pattern layer320 b is not limited to this example.

The first wavelength conversion pattern layer 320 a may receive lightand emit light having a first color. For example, the first wavelengthconversion pattern layer 320 a may receive light having a wavelengthband of a third color from a light source and convert the received lightinto light having a wavelength band of the first color.

In an embodiment, the first color may be green having a wavelength bandof about 495 to 570 nm. However, it should be understood that thewavelength band of green includes all wavelength ranges that can berecognized as green in the art.

The second wavelength conversion pattern layer 320 b may receive lightand emit light having a second color. For example, the second wavelengthconversion pattern layer 320 b may receive light having the wavelengthband of the third color from the light source and convert the receivedlight into light having a wavelength band of the second color.

In an embodiment, the second color may be red having a wavelength bandof about 620 to 750 nm. However, it should be understood that thewavelength band of red includes all wavelength ranges that can berecognized as red in the art.

The first wavelength conversion pattern layer 320 a and the secondwavelength conversion pattern layer 320 b may respectively include firstand second wavelength conversion particles 321 a and 321 b to convertthe wavelength of received light. The first and second wavelengthconverting particles 321 a and 321 b may include, for example, quantumdots, fluorescent particles, or phosphorescent particles.

In an embodiment, the first wavelength conversion pattern layer 320 amay include the first wavelength conversion particles 321 a that convertlight of the third color received from the light source into lighthaving the first color, and the second wavelength conversion patternlayer 320 b may include the second wavelength conversion particles 321 bthat convert the light of the third color received from the light sourceinto light having the second color.

The quantum dots, which are an example of the wavelength conversionparticles, are a material having a crystal structure of severalnanometers in size. The quantum dots are composed of several hundreds tothousands of atoms and exhibit a quantum confinement effect in which anenergy band gap increases due to the small size of the quantum dots.When light of a wavelength having a higher energy than a band gap isincident on the quantum dots, the quantum dots are excited by absorbingthe light and fall to a ground state while emitting light of a specific(or set) wavelength. The emitted light of the specific (or set)wavelength has a value corresponding to the band gap. Emissioncharacteristics due to the quantum confinement effect can be adjusted bycontrolling the size and composition of the quantum dots.

The quantum dots may include at least one of a group II-VI compound, agroup II-V compound, a group III-VI compound, a group III-V compound, agroup IV-VI compound, a group I-III-VI compound, a group II-IV-VIcompound, and/or a group II-IV-V compound.

A quantum dot may include a core and a shell overcoating the core. Thecore may be, but is not limited to, at least one of CdS, CdSe, CdTe,ZnS, ZnSe, ZnTe, GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InP, InGaP,InAs, InSb, SiC, Ca, Se, In, P, Fe, Pt, Ni, Co, Al, Ag, Au, Cu, FePt,Fe₂O₃, Fe₃O₄, Si, and Ge. The shell may include, but is not limited to,at least one of ZnS, ZnSe, ZnTe, ZnSeS, ZnTeS, CdS, CdSe, CdTe, HgS,HgSe, HgTe, AlN, AlP, AlAs, AlSb, GaN, GaP, GaAs, GaSb, GaSe, InN, InP,InAs, InSb, TlN, TlP, TlAs, TlSb, PbS, PbSe, and/or PbTe.

When light incident on the wavelength conversion particles is emittedafter its wavelength is converted by the wavelength conversionparticles, the emission direction of the light has random scatteringcharacteristics (Lambertian emission). Therefore, even if the wavelengthconversion pattern layers 320 having the wavelength conversion particlesdo not include a scatterer, the front and side luminance of lightemitted from the wavelength conversion pattern layers 320 may be uniformor substantially uniform. However, the wavelength conversion patternlayers 320 may further include the scatterer in order to increase lightconversion efficiency. The scatterer may be, but is not limited to, thesame or substantially the same as a scatterer 311 included in thelight-transmitting pattern layer 310 which will be described elsewhereherein.

The light-transmitting pattern layer 310 may receive light and emitlight of the third color. For example, the light-transmitting patternlayer 310 may receive light having the wavelength band of the thirdcolor from the light source and transmit the received light.

In an embodiment, the third color may be blue having a wavelength bandof about 450 to 495 nm. However, it should be understood that thewavelength band of blue includes all wavelength ranges that can berecognized as blue in the art.

The light-transmitting pattern layer 310 may be made of a transparentorganic layer in order to transmit light received from the light sourceas it is. In some embodiments, the light-transmitting pattern layer 310may include a colorant having the third color. For example, the colorantmay be a pigment, a dye, or a mixture thereof. The colorant may bedispersed in the transparent organic layer of the light-transmittingpattern layer 310. Since the light-transmitting pattern layer 310includes the colorant having the third color, the purity of the thirdcolor of light emitted from the light-transmitting pattern layer 310 canbe increased. However, embodiments are not limited to this case, and thelight-transmitting pattern layer 310 can also be made of an organiclayer having a color that transmits only the wavelength of the thirdcolor.

The light-transmitting pattern layer 310 may further include thescatterer 311. The scatterer 311 may be dispersed in thelight-transmitting pattern layer 310. The scatterer 311 scatters lightincident on the light-transmitting pattern layer 310 to make lightemitted from the light-transmitting pattern layer 310 have uniform orsubstantially uniform front and side luminance, thereby improving theviewing angle of a display device including the color conversion element1. The scatterer 311 may be any suitable material that can uniformly orsubstantially uniformly scatter light. For example, the scatterer 311may be nanoparticles such as SiO₂, TiO₂, ZrO₂, Al₂O₃, In₂O₃, ZnO, SnO₂,Sb₂O₃ and/or ITO.

The low refractive layers 400 a and 400 b may be disposed on and underthe wavelength conversion pattern layers 320 and the light-transmittingpattern layer 310. The low refractive layers 400 a and 400 b include thefirst low refractive layer 400 a and the second low refractive layer 400b disposed on and under the wavelength conversion pattern layers 320 andthe light-transmitting pattern layer 310, respectively. For example, thelow refractive layers 400 a and 400 b may cover upper and lower surfacesof the wavelength conversion pattern layers 320 and thelight-transmitting pattern layer 310.

The low refractive layers 400 a and 400 b may also be disposed on atleast part of side surfaces of the wavelength conversion pattern layers320 and the light-transmitting pattern layer 310. For example, asillustrated in the drawings, the second low refractive layer 400 b maycover not only the upper surfaces but also the side surfaces of thewavelength conversion pattern layers 320 and the light-transmittingpattern layer 310.

The first low refractive layer 400 a may be disposed as a singleintegrated layer under the first and second wavelength conversionpattern layers 320 a and 320 b and the light-transmitting pattern layer310. However, embodiments are not limited to this case, and the firstlow refractive layer 400 a may also be composed of separate layersdisposed under the wavelength conversion pattern layers 320 and thelight-transmitting pattern layer 310, respectively. In this case, thefirst low refractive layer 400 a may also not be disposed under some ofthe first and second wavelength conversion pattern layers 320 a and 320b and the light-transmitting pattern layer 310. The second lowrefractive layer 400 b may also be the same or substantially the same asthe first low refractive layer 400 a.

The low refractive layers 400 a and 400 b may have a lower refractiveindex than the wavelength conversion pattern layers 320 and thelight-transmitting pattern layer 310. The low refractive layers 400 aand 400 b may induce the total reflection of light coming from the lightconversion pattern layers 320 or the light-transmitting pattern layer310 in order to recycle the light.

For example, the first low refractive layer 400 a may reflect light,which transmits through the wavelength conversion pattern layers 320without passing through the wavelength conversion particles 321 a and321 b, in an upward direction so that the light can be incident on thewavelength conversion particles 321 a and 321 b, and the second lowrefractive layer 400 b may reflect light, which is scattered in theupward direction by the wavelength conversion particles 321 a and 321 b,in a downward direction to recycle the light. In addition, a portion ofthe second low refractive layer 400 b which is disposed on the sidesurfaces of the wavelength conversion pattern layers 320 and thelight-transmitting pattern layer 310 may play some or all of the aboveroles. Since light can be recycled due to the low refractive layers 400a and 400 b disposed on at least one surface of the wavelengthconversion pattern layers 320 and the light-transmitting pattern layer310, the light efficiency of the color conversion element 1 can beimproved.

The refractive index of each of the low refractive layers 400 a and 400b may be 1.3 or less. When the refractive index of each of the lowrefractive layers 400 a and 400 b is 1.3 or less, the difference inrefractive index between the low refractive layers 400 a and 400 b andthe wavelength conversion pattern layers 320 or the light-transmittingpattern layer 310 is large. Therefore, the total reflection of light cancertainly occur.

Embodiments of each low refractive layer 400 a or 400 b will now bedescribed in detail.

FIG. 3 is an enlarged view of a portion B of FIG. 2.

Referring to FIG. 3, each of the low refractive layers 400 a and 400 bmay include inorganic particles P, each having a hole H, and a resin R.The inorganic particles P may be dispersed in the resin R.

The inorganic particles P may include one or more of silica (SiO₂),magnesium fluoride (MgF₂), and/or iron oxide (Fe₃O₄). For example, theinorganic particles P may each include a shell S made of one or moreselected from the above materials and the hole H defined in the shell Sand surrounded by the shell S.

In an embodiment, the inorganic particles P may have a diameter D_(P) of20 to 200 nm, and the shell S may have a thickness T_(S) of 5 to 20 nm.A diameter D_(H) of the hole H may be determined by the diameter D_(P)of the inorganic particles P and the thickness T_(S) of the shell S.When the diameter D_(P) of the inorganic particles P and the thicknessT_(S) of the shell S are within the above ranges, the refractive indicesof the low refractive layers 400 a and 400 b may have relatively lowervalues than the refractive indices of the wavelength conversion patternlayers 320 and the light-transmitting pattern layer 310.

The resin R may include one or more of acryl, polysiloxane,fluorinated-polysiloxane, polyurethane, fluorinated-polyurethane,polyurethane-acrylate, fluorinated-polyurethane-acrylate, cardo binder,polyimide, polymethylsilsesquioxane (PMSSQ), poly(methyl methacrylate)(PMMA), and/or a PMSSQ-PMMA hybrid.

The weight ratio of the inorganic particles P and the resin R containedin each of the low refractive layers 400 a and 400 b may be 1.5 to 4:1.When the weight ratio of the inorganic particles P to the resin R is1.5:1 or more, the low refractive layers 400 a and 400 b may have asufficiently low refractive index of 1.3 or less. Therefore, the lowrefractive layers 400 a and 400 b can efficiently induce the totalreflection of light. When the weight ratio of the inorganic particles Pto the resin R is 4:1 or less, a reduction in the adhesion and/orchemical resistance of the low refractive layers 400 a and 400 b toadjacent layers can be prevented (or a likelihood or amount of suchreduction in adhesion and/or chemical resistance may be reduced).

Each of the low refractive layers 400 a and 400 b may be formed bycoating, baking and/or photocuring a solution that contains theinorganic particles P, the resin R, a solvent, a photoreactor, andadditives. The solvent, photoreactor and additives contained in thesolution may be removed by evaporation or reaction during thebaking/curing process.

Referring back to FIGS. 1-2, the first wavelength band filter layer 210may be disposed under the wavelength conversion pattern layers 320. Forexample, the first wavelength band filter layer 210 may be disposedbetween the base substrate 100 and the first low refractive layer 400 a.

The first wavelength band filter layer 210 may absorb or reflect lightof the third color. For example, the first wavelength band filter layer210 may be a color filter or a wavelength-selective optical filter thatabsorbs or reflects light having the wavelength band of the third colorreceived from the light source and transmits light having a longerwavelength than the third color, for example, light of the first colorand/or the second color.

As described above, the upper part of the color conversion element 1based on FIG. 1 may be placed to face the display element 10 and thenbonded to the display element 10. In this case, light emitted from thedisplay element 10 may first enter the wavelength conversion patternlayers 320 and may be converted into a wavelength of the first color orthe second color. Then, the light may be incident on the firstwavelength band filter layer 210. Here, a portion of the light of thethird color which is incident on the wavelength conversion patternlayers 320 may transmit through the wavelength conversion pattern layers320 without passing through the wavelength conversion particles 321 aand 321 b. The first wavelength band filter layer 210 may block thisportion of the light of the third color, thereby improving the purity ofthe first color and/or the second color of light output from thewavelength conversion pattern layers 320.

In an embodiment, the first wavelength band filter layer 210 may be athird color filter layer. The first wavelength band filter layer 210 maybe made of, but not limited to, an organic layer having a yellow color.

The first wavelength band filter layer 210 may be disposed only underthe first wavelength conversion pattern layer 320 a and the secondwavelength conversion pattern layer 320 b and may not be disposed underthe light-transmitting pattern layer 310. In some embodiments, a filterlayer may not be disposed under the light-transmitting pattern layer310. In some other embodiments, a color filter that transmits light ofthe third color and blocks light of the first color and blocks light ofthe second color, for example, a blue color filter may be located underthe light-transmitting pattern layer 310. The first wavelength bandfilter layer 210 may be disposed as a single integrated layer under thewavelength conversion pattern layers 320. However, as in an embodimentto be described later, the first wavelength band filter layer 210 mayalso be disposed as separate layers under the first wavelengthconversion pattern layer 320 a and the second wavelength conversionpattern layer 320 b, respectively. For example, a color filter thattransmits light of the first color (for example, a green color filter)may be disposed to correspond to the first wavelength conversion patternlayer 320 a, and a color filter that transmits light of the second color(for example, a red color filter) may be disposed to correspond to thesecond wavelength conversion pattern layer 320 b.

The second wavelength band filter layer 220 may be disposed on thewavelength conversion pattern layers 320. For example, the secondwavelength band filter layer 220 may be disposed between the wavelengthconversion pattern layers 320 and the second low refractive layer 400 b.In an embodiment, the second wavelength band filter layer 220 may beomitted. A case where the second wavelength band filter layer 220 isprovided will be hereinafter described as an example, but embodimentsare not limited to this case.

The second wavelength band filter layer 220 may reflect light of thefirst and second colors. For example, the second wavelength band filterlayer 220 may be a color filter or a wavelength-selective optical filterthat transmits light of the third color and reflects light having alonger wavelength than the third color, for example, light of the firstand second colors.

As described above, the upper part of the color conversion element 1based on FIG. 1 may be placed to face the display element 10 and thenbonded to the display element 10. In this case, a portion of lightconverted into the wavelength of the first or second color by thewavelength conversion particles 321 a or 321 b may be scattered in thedirection of the second wavelength band filter layer 220. Here, thesecond wavelength band filter layer 220 may reflect the light of thefirst and second colors in a light output direction (i.e., the downwarddirection in FIG. 1) of the color conversion element 1, therebyimproving the luminance and efficiency of the light of the first andsecond colors of the color conversion element 1.

However, since the second low refractive layer 400 b disposed on thewavelength conversion pattern layers 320 can also reflect light, whichis scattered in the upward direction by the wavelength conversionparticles 321 a and 321 b, in the downward direction, the secondwavelength band filter layer 220 can be omitted when the second lowrefractive layer 400 b is provided, as in an embodiment to be describedelsewhere herein.

The second wavelength band filter layer 220 may include one or morelayers made of an inorganic material. The inorganic material may be oneor more of silicon oxide (SiO_(x)), silicon nitride (SiN_(x)) and/orsilicon oxynitride (SiO_(x)N_(y)).

In an embodiment, the second wavelength band filter layer 220 mayinclude a plurality of low refractive layers and a plurality of highrefractive layers stacked alternately. The low refractive layers of thesecond wavelength band filter layer 220 may be layers having arelatively low refractive index as compared with adjacent layers, andthe high refractive index layers may be layers having a relatively highrefractive index as compared with adjacent layers. The transmissionwavelength band and the reflection wavelength band of the secondwavelength band filter layer 220 can be controlled by, but not limitedto, the materials of the low refractive layers and the high refractivelayers, the difference between the respective thicknesses of the lowrefractive layers and the high refractive layers and the differencebetween the respective refractive indices of the low refractive layersand the high refractive layers.

In some embodiments, the second wavelength band filter layer 220 mayinclude a silicon nitride layer and a silicon oxide layer stackedalternately. In an embodiment, the low refractive layers may be made ofa silicon oxide, and the high refractive layers may be made of a metaloxide such as titanium oxide (TiO_(x)), tantalum oxide (TaO_(x)),hafnium oxide (HfO_(x)), or zirconium oxide (ZrO_(x)). However, thestructure of the second wavelength band filter layer 220 is not limitedto this example.

The second wavelength band filter layer 220 may be disposed as a singleintegrated layer on the wavelength conversion pattern layers 320 and thelight-transmitting pattern layer 310. However, embodiments are notlimited to this case, and the second wavelength band filter layer 220may also be disposed only on the wavelength conversion pattern layers320 or may be disposed as separate layers on the first and secondwavelength conversion pattern layers 320 a and 320 b and thelight-transmitting pattern layer 310, respectively.

The overcoat layer 500 may be disposed on the second low refractivelayer 400 b. The overcoat layer 500 may be a planarization layer thatcan minimize or reduce a step formed by the lamination of a plurality oflayers, such as the wavelength conversion pattern layers 320 and the lowrefractive layers 400 a and 400 b, on the base substrate 100. Theovercoat layer 500 may cover all of the layers disposed on the basesubstrate 100 without distinction between the wavelength conversionpattern layers 320 and the light-transmitting pattern layer 310.

The overcoat layer 500 may be made of an organic material havingplanarization properties. For example, the overcoat layer 500 may bemade of thermosetting resin. The overcoat layer 500 may be made of anorganic material including one or more of cardo resin, polyimide resin,acrylic resin, siloxane resin, and/or silsesquioxane resin.

FIG. 4 is a cross-sectional view of a display device according to anembodiment.

Referring to FIG. 4, the display device includes a display element 10and a color conversion element 1 placed to face the display element 10.The color conversion element 1 may be disposed on the display element10, and the base substrate side of the color conversion element 1 may beplaced to face upward based on FIG. 4.

A plurality of pixels PX1 through PX3 may be defined in the displaydevice and arranged substantially in a matrix form in a plan view. Asused herein, ‘pixels’ refer to single regions into which a display areais divided for color display in a plan view, and one pixel may be aminimum unit that can express a color independently of other pixels. Forexample, each of the pixels PX1 through PX3 may uniquely display one ofthe primary colors to implement color display. For example, the pixelsPX1 through PX3 may include a third pixel PX3 which displays the thirdcolor, a second pixel PX2 which displays the first color having a longerpeak wavelength than the third color, and a first pixel PX1 whichdisplays the second color having a longer peak wavelength than the firstcolor.

The first pixel PX1, the second pixel PX2 and the third pixel PX3arranged adjacent to each other may form a basic unit, and the basicunit may be repeated. A case where the first color is green, the secondcolor is red and the third color is blue will be hereinafter describedas an example, but embodiments are not limited to this case.

A light-transmitting pattern layer 310, a first wavelength conversionpattern layer 320 a and a second wavelength conversion pattern layer 320b may be disposed in areas correspond to the third pixel PX3, the secondpixel PX2 and the first pixel PX1, respectively. However, this is merelyan example, and the matching relationship between the pattern layers310, 320 a and 320 b and the pixels PX1, PX2 and PX3 can be changed.

Since the color conversion element 1 has been described above, thedisplay element 10 will be described below.

The display element 10 may include a backlight unit BLU, a lowersubstrate 620, a pixel electrode 630, a liquid crystal layer 650, acommon electrode 670, a lower alignment layer 640, an upper alignmentlayer 660, a lower polarizer 610 and an upper polarizer 680.

The backlight unit BLU may be disposed under the display element 10 toprovide light having a specific (or set) wavelength to the displayelement 10. The backlight unit BLU may include a light source whichdirectly emits light and a light guide plate which guides the lightemitted from the light source toward the display element 10.

The light source may be a light emitting diode (LED) or an organic lightemitting diode (OLED). In an embodiment, the light source may emit lighthaving a shorter peak wavelength than the first color and the secondcolor. In an embodiment, the light source may emit light of the thirdcolor. The third color may be blue having a single peak wavelength inthe range of about 430 to 470 nm. For example, the backlight unit BLUcan provide light of the third color to the display element 10. In anembodiment, the light source may emit light having a peak wavelength inan ultraviolet band, and the backlight unit BLU may provide theultraviolet light to the display element 10.

The lower substrate 620 may be disposed above the backlight unit BLU.The lower substrate 620 may include a switching element, a drivingelement, etc. which constitute a thin-film transistor, and a pluralityof insulating layers. For example, the lower substrate 620 may be athin-film transistor substrate.

The pixel electrode 630 may be disposed on the lower substrate 620 ineach of the pixels PX1 through PX3. The common electrode 670 may bedisposed on the pixel electrode 630 without distinction between thepixels PX1 through PX3. The liquid crystal layer 650 may include liquidcrystals LC and may be interposed between the pixel electrode 630 andthe common electrode 670. The liquid crystals LC may have negativedielectric anisotropy and may be vertically aligned in an initialalignment state.

When an electric field is formed between the pixel electrode 630 and thecommon electrode 670, the liquid crystals LC may be tilted or rotated ina specific (or set) direction to change the polarization state of lighttransmitted through the liquid crystal layer 650. In an embodiment, theliquid crystals LC may have positive dielectric anisotropy and may behorizontally aligned in the initial alignment state.

The lower alignment layer 640 may be disposed between the pixelelectrode 630 and the liquid crystal layer 650, and the upper alignmentlayer 660 may be disposed between the common electrode 670 and theliquid crystal layer 650. The lower alignment layer 640 and the upperalignment layer 660 may induce the liquid crystals LC to have apredetermined (or set) pretilt angle in the initial alignment state.

The lower polarizer 610 may be disposed between the backlight unit BLUand the lower substrate 620, and the upper polarizer 680 may be disposedbetween the common electrode 670 and the color converting element 1. Thelower and upper polarizers 610 and 680 may be absorptive polarizer orreflective polarizers. For example, an absorptive polarizer may absorb apolarization component parallel (e.g., substantially parallel) to anabsorption axis and transmit a polarization component parallel (e.g.,substantially parallel) to a transmission axis, thereby polarizingtransmitted light. The lower and upper polarizers 610 and 680 mayperform an optical shutter function together with the liquid crystallayer 650 to control the amount of light transmitted through each of thepixels PX1 through PX3.

The arrangement of the lower and upper polarizers 610 and 680 is notlimited to that illustrated in FIG. 4, and the lower polarizer 610 canbe disposed between the lower substrate 620 and the liquid crystal layer650, and the upper polarizer 680 can be disposed between the commonelectrode 670 and the liquid crystal layer 650.

As described above, the display element 10 may be a liquid crystaldisplay element that can display an image by controlling transmittedlight through the control of the liquid crystal layer 650, and the lightsource which provides light to the color conversion element 1 locatedabove the light source may be the backlight unit BLU of the liquidcrystal display element.

However, the display element 10 of the present disclosure is not limitedto the liquid crystal display element. The display element 10 may alsobe an organic light-emitting display element (see FIG. 13) including anorganic light emitting material. The organic light-emitting displayelement may have a structure in which a light emitting layer is disposedin each pixel. Here, the structure in which the light emitting layer isdisposed in each pixel may include a structure in which the lightemitting layer is disposed in an island shape in each pixel, and/or mayinclude a structure in which the light emitting layer is continuouslydisposed in each pixel such as, for example, a structure in which thelight emitting layer is disposed over all the pixels. In this case, thelight source of the organic light-emitting display element may be thelight emitting layer, and the light emitting layer may provide light tothe color conversion element 1 located above the light emitting layer.The light emitting layer may be, but is not limited to, a single layeror a multilayer that emits blue light. In addition, unlike in theabove-described case where the color conversion element 1 ismanufactured in the form of a separate panel and then bonded to theliquid crystal display element 10 to face the liquid crystal displayelement 10, the color conversion element 1 can be formed directly on theorganic light-emitting display element. This will be described in detaillater with reference to FIG. 13.

Light emitted from the light source of the display element 10 is outputfrom the display element 10 via the backlight unit BLU, the liquidcrystal layer 650, etc. to be incident on the color conversion element1. Then, the incident light sequentially passes through an overcoatlayer 500, a second low refractive layer 400 b, a second wavelength bandfilter layer 220, wavelength conversion pattern layers 320 or alight-transmitting pattern layer 310, a first low refractive layer 400a, a first wavelength band filter layer 210 and a base substrate 100 ofthe color conversion element 1 to come out of the display device. Inthis process, light which transmits through the wavelength conversionpattern layers 320 without passing through wavelength conversionparticles 321 a and 321 b or light which is scattered back toward thedisplay element 10 by the wavelength conversion particles 321 a and 321b or a scatterer 311 may be recycled by the low refractive layers 400 aand 400 b. Thus, the light efficiency, luminance, etc. of the displaydevice can be improved.

FIG. 5 is a cross-sectional view of a color conversion element 2according to an embodiment, and FIG. 6 is an enlarged view of a portionC of FIG. 5.

The color conversion element 2 of FIGS. 5-6 is substantially the same asthe color conversion element 1 described above with reference to FIGS.1-3, except that it further includes a plurality of capping layers CLdisposed on and under each low refractive layer 400 a or 400 b.Hereinafter, any redundant description will not be repeated, and thecurrent embodiment will be described, focusing mainly on differenceswith the pervious embodiment.

Referring to FIGS. 5-6, the capping layers CL may be disposed on andunder each low refractive layer 400 a or 400 b. A first capping layerCL1 and a second capping layer CL2 may be disposed under and on a firstlow refractive layer 400 a, respectively, and a third capping layer CL3and a fourth capping layer CL4 may be disposed under and on a secondrefractive layer 400 b, respectively.

Each of the capping layers CL may be disposed directly on a lowrefractive layer 400 a or 400 b to be in contact with the low refractivelayer 400 a or 400 b. However, embodiments are not limited to this case.For example, the third capping layer CL3 may be spaced apart from thesecond low refractive layer 400 b with a second wavelength band filterlayer 220 interposed between them. When the second wavelength bandfilter layer 220 includes one or more layers made of an inorganicmaterial as described above, it can also play the role of protecting thesecond low refractive layer 400 b, and the third capping layer CL3 canbe omitted as in an embodiment to be described elsewhere herein.

Each capping layer CL may be made of an inorganic material. For example,each capping layer CL may include one or more of silicon oxide(SiO_(x)), silicon nitride (SiN_(x)), and/or silicon oxynitride(SiO_(x)N_(y)).

The low refractive layers 400 a and 400 b can be damaged in a subsequentprocess by a solvent or developer introduced by adjacent organicmaterial layers or can be damaged by outgas due to baking. Accordingly,the refractive indices of the low refractive layers 400 a and 400 b mayincrease, which, in turn, degrades the function of totally reflectinglight. For example, since wavelength conversion pattern layers 320, afirst wavelength band filter layer 210 and an overcoat layer 500 can bemade of an organic material, the function of the low refractive layers400 a and 400 b adjacent to the wavelength conversion pattern layers320, the first wavelength band filter layer 210 and the overcoat layer500 can be degraded.

However, the capping layers CL made of an inorganic material physicallyseparate and protect each of the low refractive layers 400 a and 400 bfrom adjacent organic material layers, thereby preventing an increase inthe refractive indices of the low refractive layers 400 a and 400 b (orthereby reducing the likelihood or amount of such an increase in therefractive indices).

FIG. 7 is a cross-sectional view of a color conversion element 3according to an embodiment, and FIG. 8 is an enlarged view of a portionD of FIG. 7.

The color conversion element 3 of FIGS. 7-8 is substantially the same asthe color conversion element 2 described above with reference to FIGS.5-6, except that a third capping layer CL is omitted. Hereinafter, anyredundant description will not be repeated, and the current embodimentwill be described, focusing mainly on differences with the perviousembodiment.

Referring to FIGS. 7-8, the third capping layer CL3 disposed under asecond low refractive layer 400 b, for example, between the second lowrefractive layer 400 b and wavelength conversion pattern layers 320 maybe omitted. In this case, a second wavelength band filter layer 220 mayinclude one or more layers made of an inorganic material as describedabove and may play the role of protecting the second low refractivelayer 400 b. In addition, the second wavelength band filter layer 220may be formed as a single layer containing one or more of the aboveexample inorganic materials.

FIGS. 9-10 are cross-sectional views of color conversion elements 4 and5 according to embodiments.

The color conversion elements 4 and 5 of FIGS. 9-10 are substantiallythe same as the color conversion element 2 described above withreference to FIGS. 5-6, except that a first low refractive layer 400 aor a second low refractive layer 400 b is omitted.

Referring to FIGS. 9-10, the first low refractive layer 400 a disposedunder wavelength conversion pattern layers 320 and the second lowrefractive layer 400 b disposed on the wavelength conversion patternlayers 320 may be selectively omitted according to the characteristicsof the wavelength conversion pattern layers 320, application fields ofthe color conversion elements 4 and 5, a user's preference, etc.

FIG. 11 is a cross-sectional view of a color conversion element 6according to an embodiment.

The color conversion element 6 of FIG. 11 is substantially the same asthe color conversion element 2 described above with reference to FIGS.5-6, except that a second wavelength band filter layer 220 is omitted.Hereinafter, any redundant description will not be repeated, and thecurrent embodiment will be described, focusing mainly on differenceswith the pervious embodiment.

Referring to FIG. 11, the second wavelength band filter layer 220disposed between wavelength conversion pattern layers 320 and a secondlow refractive layer 400 b may be omitted.

The second low refractive layer 400 b disposed on the wavelengthconversion pattern layers 320 can reflect light, which is scattered inthe upward direction by wavelength conversion particles 321 a and 321 b,in the downward direction. Therefore, the second low refractive layer400 b can substantially perform the function of the second wavelengthband filter layer 220. For this reason, the second wavelength bandfilter layer 220 may be omitted.

FIG. 12 is a cross-sectional view of a color conversion element 7according to an embodiment.

The color conversion element 7 of FIG. 12 is substantially the same asthe color conversion element 2 described above with reference to FIGS.5-6, except that a first wavelength band filter layer 211 is dividedinto a first sub-filter layer 211 a and a second sub-filter layer 211 b.Hereinafter, any redundant description will not be repeated, and thecurrent embodiment will be described, focusing mainly on differenceswith the pervious embodiment.

Referring to FIG. 12, the first wavelength band filter layer 211 may bedivided into the first sub-filter layer 211 a disposed under a firstwavelength conversion pattern layer 320 a and the second sub-filterlayer 211 b disposed under a second wavelength conversion pattern layer320 b.

The first sub-filter layer 211 a may transmit light of the first colorwhile blocking the transmission of light of the third color, and thesecond sub-filter layer 211 b may transmit light of the second colorwhile blocking the transmission of light of the third color.

In an embodiment, the first sub-filter layer 211 a may be made of anorganic layer having a yellow or green color, and the second sub-filterlayer 211 b may be made of an organic layer having a red color. However,each of the first and second sub-filter layers 211 a and 211 b can alsobe made of an organic layer having a yellow color.

FIG. 13 is a cross-sectional view of a display device according to anembodiment. The display device of FIG. 13 is substantially the same asthe display device described above with reference to FIG. 4, except thata display element 20 is not a liquid crystal display element 10 but anorganic light-emitting display element 20. Hereinafter, any redundantdescription will not be repeated, and the current embodiment will bedescribed, focusing mainly on differences with the pervious embodiment.

Referring to FIG. 13, the display device includes the display element 20and a color conversion element 1′ disposed directly on the displayelement 20.

The display element 20 includes a support substrate 910, a firstelectrode 920, a pixel defining layer 930, a light emitting layer 940, asecond electrode 950, and a thin-film encapsulation layer 960.

The support substrate 910 provides a space for accommodating elementssuch as the light emitting layer 940 and may be a driving substrateincluding wiring, electrodes, semiconductors, insulating layers, etc.for driving the display element 20.

The first electrode 920 may be disposed on the support substrate 910.The first electrode 920 may be disposed in an area corresponding to eachpixel PX1, PX2 or PX3 of the display element 20. The first electrode 920may be a pixel electrode or an anode of the display element 20.

The pixel defining layer 930 may be disposed on the support substrate910. In a plan view, the pixel defining layer 930 may define a pluralityof pixels in the display element 20 through openings. An opening mayexpose at least part of the first electrode 920 in each pixel.

The light emitting layer 940 may be disposed on the first electrode 920exposed by each of the openings. The light emitting layer 940 may be anorganic light-emitting layer including an organic material that emitslight through excitons formed by holes and electrons. The light emittinglayer 940 may further include one or more of a hole injection layer, ahole transport layer, an electron transport layer, and an electroninjection layer.

In some embodiments, the light emitting layers 940 respectively disposedin the pixels PX1 through PX3 may all be blue light emitting layers. Forexample, light L emitted from each light emitting layer 940 may be bluelight.

In some embodiments, each of the light emitting layers 940 may includeonly one blue light emitting layer. In some embodiments, each of thelight emitting layers 940 may include two or more blue light emittinglayers and may further include a charge generation layer located betweenthe two blue light emitting layers.

The second electrode 950 may be disposed on the light emitting layer940. The second electrode 950 may cover both the light emitting layer940 and the pixel defining layer 930. The second electrode 950 may be acommon electrode or a cathode of the display element 20.

The thin-film encapsulation layer 960 may be disposed on the secondelectrode 950. In some embodiments, the thin-film encapsulation layer960 may be disposed to cover all of the pixels PX1 through PX3. In someembodiments, a capping layer may be further disposed between thethin-film encapsulation layer 960 and the second electrode 950 to coverthe second electrode 950. In this case, the thin-film encapsulationlayer 960 may directly cover the capping layer (e.g., the thin-filmencapsulation layer 960 may physically contact the capping layer).

The thin-film encapsulation layer 960 may seal the display element 20 toprevent foreign matter or moisture from penetrating into the lightemitting layer 940 (or to reduce a likelihood or amount of thepenetration of foreign matter or moisture from penetrating into thelight emitting layer 940). The thin-film encapsulation layer 960 mayplanarize an upper surface of the display element 20.

In some embodiments, the thin-film encapsulation layer 960 may include afirst encapsulating inorganic film 961, an encapsulating organic film963, and a second encapsulating inorganic film 965 sequentially stackedon the second electrode 950.

In some embodiments, each of the first encapsulating inorganic film 961and the second encapsulating inorganic film 965 may each independentlybe made of silicon nitride, aluminum nitride, zirconium nitride,titanium nitride, hafnium nitride, tantalum nitride, silicon oxide,aluminum oxide, titanium oxide, tin oxide, cerium oxide, siliconoxynitride (SiON), or lithium fluoride.

In some embodiments, the encapsulating organic film 963 may be made ofacrylic resin, methacrylic resin, polyisoprene, vinyl resin, epoxyresin, urethane resin, cellulose resin, and/or perylene resin.

However, the structure of the thin-film encapsulation layer 960 is notlimited to the foregoing description, and the lamination structure ofthe thin-film encapsulation layer 960 can be variously changed.

The color conversion element 1′ may be disposed on the display element20, for example, on the thin-film encapsulation layer 960 of the displayelement 20.

The color conversion element 1′ includes a light shielding member BM, afirst wavelength conversion pattern layer 320 a, a second wavelengthconversion pattern layer 320 b, a light-transmitting pattern layer 310,a first low refractive layer 400 a and a second low refractive layer 400b and may further include a first wavelength band filter layer 210 and asecond wavelength band filter layer 220. Hereinafter, any redundantdescription of features that have already been described herein will notbe repeated. Rather, the following description primarily relates to thedifferences with the above description.

The first low refractive layer 400 a may be located on the thin-filmencapsulation layer 960.

The second wavelength band filter layer 220 may be located on the firstlow refractive layer 400 a. As described above, the second wavelengthband filter layer 220 may transmit light of the third color, forexample, blue light and reflect light having a longer wavelength thanthe third color, for example, red light and green light. In someembodiments, the second wavelength band filter layer 220 may be disposedover the pixels PX1 through PX3. In an embodiment, the second wavelengthband filter layer 220 may be omitted as described above.

The wavelength conversion pattern layers 320 a and 320 b and thelight-transmitting pattern layer 310 may be located on the secondwavelength band filter layer 220. The wavelength conversion patternlayers 320 a and 320 b and the light-transmitting pattern layer 310 maybe arranged to correspond to the pixels PX1 through PX3 of the displayelement 20, respectively.

The second low refractive layer 400 b may be located on the wavelengthconversion pattern layers 320 a and 320 b and the light-transmittingpattern layer 310, and the light shielding member BM may be located onthe second low refractive layer 400 b. The light shielding member BM maybe disposed to correspond to the boundary of each of the pixels PX1through PX3.

The first wavelength band filter layer 210 may be disposed on the secondlow refractive layer 400 b. In some embodiments, the first wavelengthband filter layer 210 may cover at least a part of the light shieldingmember BM. In some embodiments, the first wavelength band filter layer210 may not be disposed in the third pixel PX3 and may be disposed inboth the first pixel PX1 and the second pixel PX2. In an embodiment, thefirst wavelength band filter layer 210 may be changed to a firstsub-filter layer 211 a (see FIG. 12) corresponding to the second pixelPX2 and a second sub-filter layer 211 b (see FIG. 12) corresponding tothe first pixel PX1, as described above with reference to FIG. 12.Further, in some embodiments, a color filter of the third color, forexample, a blue color filter may be disposed in the third pixel PX3 asdescribed above.

Light L emitted from the light emitting layers 940 of the displayelement 20 is provided to the color conversion element 1′, and the colorconversion element 1′ receives the light L from the display element 20and emits light of a color corresponding to each of the pixels PX1through PX3 as described above.

For example, when light L emitted from the light emitting layer 940 inthe first pixel PX1 is blue light, the light L passes through the firstlow refractive layer 400 a and the second wavelength band filter layer220 to enter the second wavelength conversion pattern layer 320 b. Inthe second wavelength conversion pattern layer 320 b, the blue light isconverted into light of the second color (e.g., red light). The light ofthe second color is transmitted through the first wavelength band filterlayer 210 to the outside.

In addition, blue light L emitted from the light emitting layer 940 inthe second pixel PX2 passes through the first low refractive layer 400 aand the second wavelength band filter layer 220 to enter the firstwavelength conversion pattern layer 320 a. In the first wavelengthconversion pattern layer 320 a, the blue light is converted into lightof the first color (e.g., green light). The light of the first color istransmitted through the first wavelength band filter layer 210 to theoutside.

In addition, blue light L emitted from the light emitting layer 940 inthe third pixel PX3 passes through the first low refractive layer 400 aand the second wavelength band filter layer 220 to enter thelight-transmitting pattern layer 310. Then, the blue light L istransmitted through the light-transmitting pattern layer 310 to theoutside.

FIG. 14 is a cross-sectional view of a display device according to anembodiment. The display device of FIG. 14 is substantially the same asor similar to the embodiment of FIG. 13 except for the position of acolor conversion element 1′″. Hereinafter, any redundant description offeatures that have already been described herein will not be repeated.Rather, the following description primarily relates to the differenceswith the above description.

The color conversion element 1″ faces a display element 20.

The color conversion element 1″ includes a substrate 800, a lightshielding member BM, a first wavelength conversion pattern layer 320 a,a second wavelength conversion pattern layer 320 b, a light-transmittingpattern layer 310, a first low refractive layer 400 a, and a second lowrefractive layer 400 b, and may further include a first wavelength bandfilter layer 210 and a second wavelength band filter layer 220.

The light shielding member BM is located on the surface of the substrate800 facing the display element 20 and is disposed to correspond to theboundary of each pixel PX1, PX2 or PX3.

The first wavelength band filter layer 210 is located on the surface ofthe substrate 800 and is disposed to correspond to the first pixel PX1and the second pixel PX2. However, embodiments are not limited to thiscase, and the first wavelength band filter layer 210 may also be changedto be a first sub-filter layer 211 a (see FIG. 12) corresponding to thesecond pixel PX2 and a second sub-filter layer 211 b (see FIG. 12)corresponding to the first pixel PX1 as described above. In someembodiments, the first wavelength band filter layer 210 may cover thelight shielding member BM. In some embodiments, a color filter of thethird color, for example, a blue color filter corresponding to the thirdpixel PX3 may also be disposed on the surface of the substrate 800 asdescribed above.

The first low refractive layer 400 a may be disposed on the firstwavelength band filter layer 210 and may be disposed over the pixels PX1through PX3.

The wavelength conversion pattern layers 320 a and 320 b and thelight-transmitting pattern layer 310 may be located on the first lowrefractive layer 400 a.

The second wavelength band filter layer 220 may be disposed on thewavelength conversion pattern layers 320 a and 320 b and thelight-transmitting pattern layer 310, and the second low refractivelayer 400 b may be disposed on the second wavelength band filter layer220.

A filler 700 may be located between the second low refractive layer 400b and a thin-film encapsulation layer 960.

FIG. 15 is a cross-sectional view of a display device according to anembodiment. The display device of FIG. 15 is substantially the same asor similar to the embodiment of FIG. 14, except that a color conversionelement 1′″ does not include a first wavelength band filter layer (210in FIG. 14) and includes a first sub-filter layer 211 a, a secondsub-filter layer 211 b, and a third sub-filter layer 211 c. Hereinafter,any redundant description of features that have already been describedherein will not be repeated. Rather, the following description primarilyrelates to differences with the above description.

The first sub-filter layer 211 a, the second sub-filter layer 211 b, andthe third sub-filter layer 211 c may be located on a surface of thesubstrate 800 as described above.

The first sub-filter layer 211 a may block light of the third color andlight of the second color and transmit light of the first color. Forexample, the first sub-filter layer 211 a may be a green color filter.

The second sub-filter layer 211 b may block light of the third color andlight of the first color and transmit light of the second color. Forexample, the second sub-filter layer 211 b may be a red color filter.

The third sub-filter layer 211 c may block light of the first color andlight of the second color and transmit light of the third color. Forexample, the third sub-filter layer 211 c may be a blue color filter. Insome embodiments, the third sub-filter layer 211 c may be omitted as inthe above-described embodiments.

In some embodiments, each of the color conversion elements of theembodiments of FIGS. 13 through 15 may further include a plurality ofcapping layers as in the embodiment of FIG. 5 and the embodiment of FIG.7. In addition, each of the color conversion elements of the embodimentsof FIGS. 13 through 15 may be changed to have a structure in which thefirst low refractive layer 400 a and the second low refractive layer 400b are omitted as in the embodiment of FIG. 9 or may be changed to have astructure in which the second wavelength band filter layer 220 isomitted as in the embodiment of FIG. 11.

While the subject matter of the present disclosure has been particularlyillustrated and described with reference to exemplary embodimentsthereof, it will be understood by those of ordinary skill in the artthat various changes in form and detail may be made therein withoutdeparting from the spirit and scope of the present disclosure as definedby the following claims. The exemplary embodiments should be consideredin a descriptive sense only and not for purposes of limitation.

Embodiments provide at least one of the following features.

A low refractive layer disposed on and under a layer containingwavelength conversion particles or a scatterer enables light to berecycled, thereby improving light efficiency, luminance, etc.

A capping layer disposed on and under the low refractive layer canprevent the low refractive layer from being damaged by an adjacentorganic material layer in a subsequent process (or can reduce alikelihood or amount of such damage). Therefore, the function of the lowrefraction layer is not degraded.

However, the effects of the embodiments are not restricted to the oneset forth herein. The above and other effects of the embodiments willbecome more apparent to one of daily skill in the art to which theembodiments pertain by referencing the claims.

As used herein, the terms “substantially,” “about,” and similar termsare used as terms of approximation and not as terms of degree, and areintended to account for the inherent deviations in measured orcalculated values that would be recognized by those of ordinary skill inthe art. Further, the use of “may” when describing embodiments of thepresent disclosure refers to “one or more embodiments of the presentdisclosure.” As used herein, the terms “use,” “using,” and “used” may beconsidered synonymous with the terms “utilize,” “utilizing,” and“utilized,” respectively. Also, the term “exemplary” is intended torefer to an example or illustration. In the drawings, the relative sizesof elements, layers, and regions may be exaggerated for clarity.

Also, any numerical range recited herein is intended to include allsub-ranges of the same numerical precision subsumed within the recitedrange. For example, a range of “1.0 to 10.0” is intended to include allsubranges between (and including) the recited minimum value of 1.0 andthe recited maximum value of 10.0, that is, having a minimum value equalto or greater than 1.0 and a maximum value equal to or less than 10.0,such as, for example, 2.4 to 7.6. Any maximum numerical limitationrecited herein is intended to include all lower numerical limitationssubsumed therein, and any minimum numerical limitation recited in thisspecification is intended to include all higher numerical limitationssubsumed therein. Accordingly, Applicant reserves the right to amendthis specification, including the claims, to expressly recite anysub-range subsumed within the ranges expressly recited herein.

What is claimed is:
 1. A color conversion element comprising: awavelength conversion layer; one or more low refractive layers which aredisposed on and/or under the wavelength conversion layer and have alower refractive index than the wavelength conversion layer; and one ormore capping layers which are disposed between the wavelength conversionlayer and the low refractive layers and/or on a surface opposite to asurface of each of the low refractive layers which faces the wavelengthconversion layer.
 2. The color conversion element of claim 1, whereinthe capping layers comprise one or more of silicon oxide (SiO_(x)),silicon nitride (SiN_(x)) and silicon oxynitride (SiO_(x)N_(y)).
 3. Thecolor conversion element of claim 1, wherein each of the low refractivelayers comprises inorganic particles, each of the inorganic particleshaving a hole.
 4. The color conversion element of claim 3, wherein eachof the low refractive layers further comprises a resin, and theinorganic particles are dispersed in the resin.
 5. The color conversionelement of claim 4, wherein a weight ratio of the inorganic particlesand the resin contained in each of the low refractive layers is 1.5:1 to4:1.
 6. The color conversion element of claim 3, wherein the inorganicparticles comprise one or more selected from silica (SiO₂), magnesiumfluoride (MgF₂), and iron oxide (Fe₃O₄).
 7. The color conversion elementof claim 1, wherein the refractive index of each of the low refractivelayers is 1.3 or less.
 8. The color conversion element of claim 1,further comprising a first wavelength band filter layer which isdisposed under a lower one of the low refractive layers, wherein atleast one of the capping layers is disposed between the lower one of thelow refractive layers and the first wavelength band filter layer.
 9. Thecolor conversion element of claim 8, further comprising a secondwavelength band filter layer which is disposed between the wavelengthconversion layer and an upper one of the low refractive layers andcomprises one or more of silicon oxide (SiO_(x)), silicon nitride(SiN_(x)) and silicon oxynitride (SiO_(x)N_(y)), wherein no cappinglayer is disposed between the upper one of the low refractive layers andthe wavelength conversion layer.
 10. The color conversion element ofclaim 1, further comprising an overcoat layer which is disposed on theupper one of the low refractive layers, wherein at least one of thecapping layers is disposed between the upper one of the low refractivelayers and the overcoat layer.
 11. The color conversion element of claim1, wherein the low refractive layers are disposed on at least part ofside surfaces of the wavelength conversion layer.
 12. A display devicecomprising: a display element; and a color conversion element which isdisposed on the display element, wherein the color conversion elementcomprises: a base substrate; a wavelength conversion pattern layer whichis disposed on the base substrate; a first low refractive layer which isdisposed between the base substrate and the wavelength conversionpattern layer and/or a second low refractive layer which is disposed onthe wavelength conversion pattern layer; and one or more capping layerswhich are disposed on and/or under the first low refractive layer and/orthe second low refractive layer, wherein each of the first lowrefractive layer and the second low refractive layer has a lowerrefractive index than the wavelength conversion pattern layer.
 13. Thedisplay device of claim 12, wherein at least one of the capping layersis disposed between the first low refractive layer and the wavelengthconversion pattern layer and/or between the second low refractive layerand the wavelength conversion pattern layer.
 14. The display device ofclaim 12, further comprising a first wavelength band filter layer whichis disposed between the base substrate and the first low refractivelayer and absorbs or reflects light of a color provided from the displayelement.
 15. The display device of claim 14, wherein at least one of thecapping layers is disposed between the first wavelength band filterlayer and the first low refractive layer.
 16. The display device ofclaim 14, further comprising a second wavelength band filter layer whichis disposed between the wavelength conversion pattern layer and thesecond low refractive layer and reflects light of a color different fromthe color of the light provided from the display element.
 17. Thedisplay device of claim 16, wherein the second wavelength band filterlayer comprises one or more selected from silicon oxide (SiO_(x)),silicon nitride (SiN_(x)) and silicon oxynitride (SiO_(x)N_(y)), and nocapping layer is disposed between the second low refractive layer andthe wavelength conversion pattern layer.
 18. The display device of claim12, further comprising an overcoat layer which is disposed on the secondlow refractive layer.
 19. The display device of claim 18, wherein atleast one of the capping layers is disposed between the second lowrefractive layer and the overcoat layer.
 20. The display device of claim12, wherein the second low refractive layer is also disposed on at leastpart of side surfaces of the wavelength conversion pattern layer.